/* PURE CSS - FLAT DESIGN - MOBILE FIRST */
        :root {
            --bg-base: #000000;
            --bg-panel: #111111;
            --bg-element: #1a1a1a;
            --bg-hover: #2a2a2a;
            --border: #333333;
            --text-main: #ffffff;
            --text-dim: #999999;
            --primary: #0055ff;
            --primary-hover: #0044cc;
            --danger: #cc0000;
            --danger-hover: #aa0000;
            --danger-text: #ff4444;
            --advanced-border: #552288;
            --advanced-bg: #14101a;
            --glitch-border: #ff3366;
            --glitch-bg: #1a0d14;
        }

        * { box-sizing: border-box; }

        /*
         * Compositeur GPU (calques) : scroll, panneau, overlay et zoom canvas plus fluides.
         * Éviter will-change partout = trop de mémoire vidéo. Le traitement VHS (Canvas 2D + getImageData)
         * reste surtout CPU : seul WebGL ou filtres CSS sur une couche pourraient déporter les pixels GPU.
         */
        body {
            margin: 0; padding: 0;
            background-color: var(--bg-base);
            color: var(--text-main);
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
            display: flex;
            flex-direction: column;
            height: 100dvh;
            overflow: hidden;
            font-size: 13px;
        }

        .workspace,
        .viewport,
        header,
        .drop-zone,
        .viewport-controls,
        .overlay,
        .overlay img,
        .overlay video,
        #main-canvas,
        button,
        input,
        select,
        textarea,
        .param-group,
        .section-title,
        .check-item {
            transform: translateZ(0);
            backface-visibility: hidden;
        }

        .hidden { display: none !important; }

        header {
            height: 50px;
            background-color: var(--bg-panel);
            border-bottom: 1px solid var(--border);
            display: flex;
            align-items: center;
            justify-content: flex-end;
            padding: 0 8px;
            gap: 6px;
            flex-shrink: 0;
        }

        button {
            background-color: var(--bg-element);
            color: var(--text-main);
            border: 1px solid var(--border);
            padding: 6px 10px;
            cursor: pointer;
            font-size: 12px;
            display: inline-flex;
            align-items: center;
            justify-content: center;
            gap: 6px;
            transition: background-color 0.2s;
        }
        button:hover { background-color: var(--bg-hover); }
        button.primary { background-color: var(--primary); border-color: var(--primary); font-weight: bold; }
        button.primary:hover { background-color: var(--primary-hover); }
        button.danger { background-color: var(--bg-element); border-color: var(--danger); color: var(--danger-text); }
        button.danger:hover { background-color: rgba(204, 0, 0, 0.2); }
        button.danger-solid { background-color: var(--danger); border-color: var(--danger); color: var(--text-main); font-weight: bold; }
        button.danger-solid:hover { background-color: var(--danger-hover); }
        button.w-full { width: 100%; margin-bottom: 8px; }

        .workspace {
            display: flex;
            flex: 1;
            overflow: hidden;
            position: relative;
        }

        .viewport {
            flex: 1;
            position: relative;
            background-color: var(--bg-base);
            overflow: hidden;
            cursor: grab;
            display: flex;
            align-items: center;
            justify-content: center;
        }
        .viewport:active { cursor: grabbing; }

        #canvas-container {
            position: absolute;
            top: 0; left: 0;
            transform-origin: 0 0;
            border: 1px solid var(--border);
            will-change: transform;
        }
        canvas { display: block; image-rendering: pixelated; }
        video { display: none; }

        .drop-zone {
            position: absolute;
            top: 20px; left: 20px; right: 20px; bottom: 70px;
            border: 2px dashed var(--border);
            background-color: var(--bg-panel);
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            z-index: 10;
        }
        .drop-zone.drag-over { border-color: var(--primary); background-color: var(--bg-element); }
        .drop-zone p { font-size: 16px; font-weight: bold; text-align: center; padding: 0 10px; }

        .viewport-controls {
            position: absolute;
            bottom: 0; left: 0; right: 0;
            min-height: 50px;
            background-color: var(--bg-panel);
            border-top: 1px solid var(--border);
            display: flex;
            flex-wrap: wrap;
            align-items: center;
            justify-content: space-between;
            padding: 8px 16px;
            gap: 12px;
            z-index: 20;
        }
        .playback-group { display: flex; align-items: center; gap: 12px; flex: 1 1 250px; }
        .playback-group input[type="range"] { flex: 1; }
        .tools-group { display: flex; align-items: center; flex-wrap: wrap; gap: 12px; flex-shrink: 0; }
        .time-display { font-family: monospace; color: var(--text-dim); min-width: 80px; }

        .sidebar {
            width: 320px;
            background-color: var(--bg-panel);
            border-left: 1px solid var(--border);
            display: flex;
            flex-direction: column;
            flex-shrink: 0;
            z-index: 30;
            transform: translateZ(0);
            backface-visibility: hidden;
        }
        .sidebar-header {
            padding: 12px 16px;
            border-bottom: 1px solid var(--border);
            font-weight: bold;
            display: flex;
            justify-content: space-between;
            background-color: #050505;
        }
        .sidebar-content {
            flex: 1;
            overflow-y: auto;
            padding: 16px;
            padding-bottom: 80px; 
        }

        .param-group {
            background-color: var(--bg-element);
            border: 1px solid var(--border);
            padding: 12px;
            margin-bottom: 16px;
        }
        .param-group.advanced { background-color: var(--advanced-bg); border-color: var(--advanced-border); }
        .param-group.glitch { background-color: var(--glitch-bg); border-color: var(--glitch-border); }
        
        .param-group h3 {
            margin: 0 0 12px 0;
            font-size: 11px;
            text-transform: uppercase;
            color: var(--text-dim);
            letter-spacing: 1px;
            display: flex;
            justify-content: space-between;
            align-items: center;
            border-bottom: 1px solid var(--border);
            padding-bottom: 6px;
        }
        .param-group.advanced h3 { color: #b388ff; border-bottom-color: var(--advanced-border); }
        .param-group.glitch h3 { color: #ff6699; border-bottom-color: var(--glitch-border); }

        .control-row { margin-bottom: 12px; }
        .control-row:last-child { margin-bottom: 0; }
        .control-label {
            display: flex;
            justify-content: space-between;
            margin-bottom: 4px;
            font-size: 12px;
            color: var(--text-dim);
        }
        .control-value { font-family: monospace; color: var(--text-main); }
        .control-value.red-zone { color: var(--danger-text); font-weight: bold; }
        
        input[type="range"] {
            -webkit-appearance: none;
            width: 100%;
            background: transparent;
            margin: 4px 0;
        }
        input[type="range"]:focus { outline: none; }
        input[type="range"]::-webkit-slider-runnable-track {
            width: 100%;
            height: 4px;
            background: var(--border);
            border-radius: 2px;
        }
        input[type="range"]::-webkit-slider-thumb {
            -webkit-appearance: none;
            width: 14px;
            height: 14px;
            border-radius: 50%;
            background: var(--text-main);
            margin-top: -5px;
            cursor: pointer;
        }
        
        select {
            width: 100%;
            background-color: #000;
            color: var(--text-main);
            border: 1px solid var(--border);
            padding: 8px 6px;
            font-size: 13px;
            margin-bottom: 12px;
            cursor: pointer;
        }

        .check-group { display: flex; gap: 12px; margin-bottom: 12px; flex-wrap: wrap; }
        .check-item { display: flex; align-items: center; gap: 6px; cursor: pointer; color: var(--text-dim); font-size: 12px; }

        .grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; margin-bottom: 12px;}
        .grid-3 { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 8px; margin-bottom: 12px;}
        .grid-4 { display: grid; grid-template-columns: 1fr 1fr 1fr 1fr; gap: 8px; margin-bottom: 12px;}
        .grid-col { display: flex; flex-direction: column; align-items: center; }
        .grid-col span { margin-top: 4px; font-size: 10px; font-family: monospace; }

        .section-title {
            font-size: 14px; font-weight: bold; color: var(--text-main);
            margin: 24px 0 12px 0; padding-bottom: 4px; border-bottom: 2px solid var(--border);
        }

        .overlay {
            position: absolute;
            top: 0; left: 0; right: 0; bottom: 0;
            background-color: rgba(0,0,0,0.95);
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            z-index: 100;
        }
        .overlay h2 { margin: 0 0 8px 0; font-size: 20px; color: var(--text-main); text-align: center; }
        .overlay p { margin: 0 0 16px 0; color: var(--text-dim); font-family: monospace; font-size: 14px; font-weight: bold; text-align: center;}
        .overlay video, .overlay img {
            max-width: 90%; max-height: 45vh; object-fit: contain;
            border: 1px solid var(--border); background: #000;
        }

        @media (max-width: 768px) {
            .sidebar {
                position: absolute;
                bottom: 0; left: 0; right: 0;
                width: 100%; height: 60dvh;
                border-left: none; border-top: 1px solid var(--border);
                transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
                transform: translate3d(0, 100%, 0);
            }
            .sidebar.is-open { transform: translate3d(0, 0, 0); }
            
            .viewport { transition: height 0.3s cubic-bezier(0.16, 1, 0.3, 1); height: 100%; }
            .viewport.panel-open { height: calc(100dvh - 60dvh - 50px); align-self: flex-start; }
            
            .playback-group { flex: 1 1 100%; }
            .tools-group { flex: 1 1 100%; justify-content: center; }
            
            #btn-menu-mobile { display: inline-flex; }
            header { justify-content: center; flex-wrap: wrap; }
        }
        @media (min-width: 769px) { #btn-menu-mobile { display: none; } }